The invention relates to an in vitro method for determining the metabolic status of a lymphoma comprising a step of determining the level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in lymphoma cells, wherein a low level of GAPDH expression is indicative of oxidative phosphorylation (OXPHOS) status. The invention also relates to an in vitro method for predicting the responsiveness of a patient afflicted with a lymphoma to a treatment with a metabolic inhibitor selected from the group consisting of mitochondrial metabolic inhibitors and glutamine metabolism inhibitors comprising a step of determining the level of GAPDH expression in lymphoma cells obtained from said patient, wherein a low level of GAPDH expression is predictive of a response to a treatment with a metabolic inhibitor.
